"IMSCREWS 5/16 x 3-1/2 Heavy-Duty Lag Screws - 304 Stainless Steel (10 pcs)

Deep Reach for Structural Timber Connections
When your project demands deep penetration and unyielding holding power, these 3.5-inch lag bolts provide the industrial strength needed. Optimized for securing deck railing posts, heavy gate frames, or structural brackets to 4x4 posts. The 5/16 diameter offers elite shear resistance for critical load-bearing joints.

Vise-Like Clamping with Partial Threading
Our partially threaded shank features a smooth upper section that allows the bolt to pull the outer timber tightly against the support beam. This creates a gap-free, rock-solid joint, eliminating the bridging effect where boards remain loose—a common failure in long full-thread screws for structural framing.

304 Stainless Exterior Defense
Forged from premium 18-8 (304) Stainless Steel for ultimate weather resistance. compatible with ACQ pressure-treated lumber. Resists rust in humid environments and prevents unsightly rust streaks on high-value cedar, redwood, or deck framing.

Technical FAQ
¡ñ Tools Required: Fits a standard 1/2 hex socket or wrench.
¡ñ Pre-drilling: Recommended to prevent timber splitting. Use a 3/16 bit for softwoods or 7/32 bit for hardwoods.
¡ñ Why 3-1/2 length? Perfect for passing through 1.5 or 2 timber with a deep 1.5 + thread anchor in the base post.
¡ñ Resilience: Rated for marine, coastal, and high-humidity environments.

Specifications:
- Size: 5/16 x 3-1/2
- Thread: Partially Threaded (Max Clamping)
- Material: 304 Stainless Steel (18-8)
- Drive: 1/2 Hex Head
- Qty: 10 pcs"

Key Features

• ELITE CLAMPING POWER The partially threaded design ensures the smooth shank stays in the outer board, allowing the threads to pull timber members together with immense force for a gap-free joint.
• IDEAL FOR 2x4 TO POSTS At 3.5 inches long, these screws provide the perfect structural anchoring depth for connecting standard 2x lumber to 4x4 or 6x6 posts without over-penetration.
• 304 EXTERIOR DEFENSE Forged from premium 304 (18-8) stainless steel to prevent rust and staining in cedar, redwood, or ACQ pressure-treated lumber projects.
• STABLE TORQUE INTERFACE Precision-forged hex head fits 1/2 sockets securely, offering stable torque transfer for controlled, slip-free seating even in dense timber cores.
• TECHNICAL SPECIFICATION To prevent timber splitting from the robust 5/16 diameter, pre-drilling a pilot hole (7/32 for softwoods, 1/4 for hardwoods) is mandatory.

Specifications

• ASIN: B0F21CDVZ2
• Internal SKU: IMS0646
• Size: 5/16" x 3-1/2"
• Material: Stainless Steel
• Finish: Stainless Steel
• Head Style: Hex
• Package Quantity: 10